Just saw an ad for a qualified math teacher at an international school for 75K a month. That's just over 400 quid a week and it's in Bangkok. Bangkok is not all that cheap. This is an international school, so they'll be asking for all the best qualifications and experience.
At the very least, the candidate will be expected to have a degree in maths and a PGCE (or equivalent). They will likely have to have several years of teaching experience in their own country. They probably aren't going to be provided with a pension (I am almost certain of this). They won't be entitled to any form of social welfare (despite paying taxes out of this measly sum) and they'll likely be worked to the bone.
I have a friend in Vietnam who works at an international school as a maths teacher and he's on double this salary. He doesn't even have qualified teacher status but he is good at what he does.